1. Field of the Invention
The present invention relates to a mechanistic apparatus used for replacing a tubular means, and more particularly relates to an injector robot used for replacing a gas injector in a furnace.
2. Description of the Prior Art
FIG. 1 illustrates a schematic structure of a vertical furnace 100. The vertical furnace 100 is equipped with a thermal insulating cover 102 within. Within the internal area of the thermal insulating cover 102, an outer quartz tube 104, an inner quartz tube 106 and a plurality of heaters 108 are arranged to form a process tube 110 with a cylindrical space. Various reaction gases used in the process tube 110 are introduced by gas supply conduits 112 and gas injectors 116 and are finally discharged by gas exhaust conduits 114. The gas injector 116 is used to conduct the reaction gas and release it at the designate position in the process tube 110. Plurality of semiconductor substrates such as silicon wafer is housed in a quartz-made boat 120, which is mounted on a platform 118 of a boat elevator 120. Hence, during a thermal oxidation process, wafers carried by the boat 120 will be moved upward into the process tube 110 and finally moved downward from the process tube 110 by the supporting of the boat elevator 120 in the vertical furnace 100.
After a certain amount of thermal chemical processing deposition, the gas injector 116 must be dropped from the vertical furnace 100 and replaced by a new one. In a conventional gas injector replacing process, the temperature within the process tube 110 must be cooled down to about 400-500xc2x0 C., then an operator that wearing heat-insulating gloves can pull out the gas injector 116 from the gas supply conduit 114. Afterward, to the contrary of the above-described operation, a new gas injector 116 with same or different specification is provided and inserted into the gas supply conduit 114, then the process tube 110 will be heated up to the normal operating temperature (ex. usually about 600xc2x0 C.). But during the replacing process, an unexpected-breaking gas injector 116 will probably scald the furnace operator standing below the process tube 110. Alternatively, another method for replacing the gas injector is adopted to stop the operation of the vertical furnace 100 until the temperature, within the process tube 110, is cooled to room temperature for lowering the danger to the furnace operator. But it will take about 4-5 hours for the cooling and reheating steps and delay the predetermined program of the vertical furnace 100.
In the two above conventional gas injector replacing processes, frequently cooling and reheating processes executed in the vertical furnace 100 will chap the reactive film coated on the wall of the process tube 110, thus particle pollution will occur in the vertical furnace 100. Besides, the above manual operations for replacing the gas injectors 116 are difficult to control because the length of the gas injectors 116 always exceed over 1 meter, and the furnace operator can not guarantee that he/she could insert the gas injector 116 into the gas supply conduit 112 with a parallel and unsloping angle.
Therefore, a mechanistic assistant apparatus is proved necessary for the operator to replace the gas injector 116 in the vertical furnace 100, which is still running and without any cooling and reheating action. Then the replacement of the gas injector 116 could be executed precisely and safely by the assistant means and will not affect the predetermined procedure of the vertical furnace 100.
As above descriptions, one object of the present invention is providing an injector robot for replacing a gas injector in a furnace precisely and safely and will not delay the predetermined procedure of the furnace.
Another object of the present invention is providing an injector robot and mounting it on a boat elevator in a furnace, without spending extra money to assemble other assistant elevator. Hence, the injector robot could be moved smoothly in the vertical direction by the supporting of the boat elevator in the furnace.
According to the above objects, the present invention is providing an injector robot for replacing a gas injector in a furnace. The injector robot is composed of a base placed on the boat elevator, a slide rail arranged on the base, and a support stand mounted to the slide rail. The top of the support stand is provided with a notch structure used to hold the gas injector, and then a chuck fixed to the support stand will help to stabilize the gas injector. In addition, the slide rail is used to provide a horizontal-moving track for the support stand. Hence, by the above designs and the utilization of the boat elevator, the injector robot could execute the gas injector replacement process in the furnace, and which is still running and without any cooling and reheating action as in the conventional replacement processes.
Additional objects and advantages of this invention will be apparent from the following detailed description of a preferred embodiment thereof that proceeds with reference to the accompanying drawings.